4S or 3S battery?
« on: September 13, 2016, 12:41:44 pm »
I am new to RC electric RC and have two planes, the PZ P-47 which takes a 3s 2200mah lipo and an Airfiled bf109 which came with a 4s 2200mah lipo. Apparently the bf109 can take batteries from 2-4s. My question is what is the difference between a 3s and a 4s lipo that has the same mah (2200 in this case) assuming the C rating was the same on both batteries (20C)

Would I get longer flight times with the 4s 14.8v battery than with the 11.1v 3s battery?
« Last Edit: October 27, 2016, 10:26:36 am by f5soh »


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Re: 4S or 3S battery?
« Reply #1 on: September 13, 2016, 02:15:19 pm »
The difference between 3s and 4s is the number of cells and consequently voltage. Battery 4s is heavier but has higher voltage than 3s.
Given example motor 1000kV which spins approximately 1000 times per volt, you would get more power with higher voltage battery. For the same reason there are HV batteries. This is useful for acro flying where you want more thrust. The C rating will tell you how much and how long that amount of voltage can be delivered at specific current before it stalls.
I don't think you will see benefit in flight time, as 4S is heavier than 3S, but your aircraft will be more powerful. It's ok to use 4S as long as you're not exceeding max ratting of your hardware.

Charging My 5200mah Batteries
« Reply #2 on: September 19, 2016, 10:58:52 am »
I am new to this all, so please bear with me - I am charging my batteries and have all the correct selections in the charger etc.

However when I go to test the voltage afterwards it shows up as 24.4volts - even though it's a 22.2v lipo battery ? Is this meant to happen, or have I done something wrong?
« Last Edit: October 27, 2016, 10:26:21 am by f5soh »


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Re: Charging My 5200mah Batteries
« Reply #3 on: September 19, 2016, 11:19:46 am »
Nominal voltage of each cell is 3.7V: 3.7x6= 22.2V
Full charge voltage is 4.2V per cell: 4.2x6=25.2V fully charged

Be sure you use the "LiPo" program in your charger and set the charging current at 1C max.
This mean 5.2A maximum for a 5200mAh battery capacity.

That just a base, most battery allow bigger charge currents.
Another limitation is charger that can sustain 150W max for example.

If you don't trust your battery you should also use the balance connector and check each cell voltage.

Useful Tips Here! Beginners's guide in choosing RC lipo batteries
« Reply #4 on: October 15, 2016, 09:13:09 am »
I am sure many beginners prefer look up forums for advice about rc lipo battery, like which brand to choose, and which item to fly, there are many posts, and some are totally different opinions.

Something you need to know before you make your choice;

1st, about cheap batteries, Many people recommend some website that sells at super low price, and tell you it's no difference with the big brands, but actually most of them have not tried other big brands, so they feel it is enough power because it is cheap and it can make the drone fly. If it is for practice, choose some well known brands like zippy, and some well known shop like RMRC or get fpv, and sure Tattu always have good quality ones sell under 10$.

2nd, High level ones.Choose what people recommend most and what famous pilots use. There are always some people saying Tattu is over priced or it is no good at all, I am sure between those, maybe one or two is real, but the rest could be coming from the competitor, Now more and more famous pilots just use tattu or tattu rline for big race, sponsor or not sponsor, Tattu makes them have faith.

Result from the just ended ERSA cup:
1. Individual Race 1s t: Luke Banister
2. Team Race 1st : Team Flyduino Kiss team
3. Drag race winner : Team Tonardo X blade with Sky-hero design frame and Tattu R-Line lipo battery
Congratulations !

« Last Edit: October 27, 2016, 10:26:05 am by f5soh »

How to choose the charger?
« Reply #5 on: October 19, 2016, 07:53:05 am »
I have a Gens ace 4s lipo battery 5000mah, what can I choose the charger and how long to charge?
Capacity: 5000mah
Voltageļ¼š 14.8V
Configuration: 4s1p
Connector Type: Deans
Could you suggest one for me ? Thanks in advance.
« Last Edit: October 27, 2016, 10:25:45 am by f5soh »


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Re: 4S or 3S battery?
« Reply #6 on: October 20, 2016, 04:57:50 am »
for long life of Lipo battery use...you should use LIPO BALANCER CHARGER.
you can use for battery storage, balance and else...
and this not just for lipo, can used for LI-Ion, NIMH, NI-CAD.
Thank You

Eddy Saputra

Re: How to choose the charger?
« Reply #7 on: October 21, 2016, 08:35:18 am »
I have a Gens ace 4s lipo battery 5000mah, what can I choose the charger and how long to charge?
Capacity: 5000mah
Voltageļ¼š 14.8V
Configuration: 4s1p
Connector Type: Deans
Could you suggest one for me ? Thanks in advance.

Personally I have Hyperion lipo chargers that I luckily caught on sale at robotbirds in UK at different times. Don't know where you're based.
the EOS 5idp AC/DC with external lba10 balancer. charges practically anything up to 5A, from mains power or 12Vdc supply
really versatile and brings 'dead' batteries back to life!
more recently also picked up:EOS0606i AC/DC https://www.robotbirds.co.uk/default/chargers-power-supply-leads/discontinued-hyperion-chargers/hyperion-eos-0606i-acdc-c-chg-bal-v2-was-a-89-95.html
which can charge up to 6A and has built in balance port, again plug in mains or use from 12V battery.
I race cars, and am quite new to quads and flight, but this is great for 1s 3.7V at track in my RC car, 3s and 4s flight pack, 2s car packs, life and lipo Tx pack, even for the little 1s from the hubsan. I may well get another if they don't sell-out.

For your pack I would suggest lipo setting for 4S at 5 Amps (which is 1x Capacity rating / 1C) balance charge i.e plug in the balancer port/ adapter as well.
The charging time depends on how flat it is to start with. max charging time would be almost an hour.
do not over-discharge, would be worth getting a batt alarm gadget that monitors cell voltage when your flying.

Hope that helps


Re: 4S or 3S battery?
« Reply #8 on: November 10, 2016, 01:30:51 am »
The math says that a 2000mah 3s has as much energy as a 1500 4s.  See how they both multiply out to 6000?  They both also weigh the same.  That means that one hovers for the same length of time as the other.  In the real world, a larger, slower prop is more efficient and a smaller faster prop will go faster but not last as long.  You need to run a significantly smaller prop on the 4s if the motor is the same, but the 4s with smaller prop will actually give you more top speed and max thrust.

Set up for 3s now and if you really want the extra power and speed later, get a 4s and some smaller props.

As a starting place, a 3s 2200mah lipo and a 2212 KV920 motor, a 25 to 30 amp ESC, and a 10x4.5 (I actually cut my 10 inch props down to 9 inch for KV1000 motors) prop are fairly well matched.

The first thing a beginner should do is have someone who knows how to match a battery / motor / prop / ESC tell him what to get for a particular model.  Of course an RTF model fits this bill nicely as the designer has done the matching for you.

The second thing a beginner should do is buy and understand usage of a standard Lipo charger for the size of batteries he will be using.

The third thing a beginner should do is buy several Lipo alarms to keep him from over discharging his Lipos.  Get several of these.  They watch cells individually through the balance connector (that is very desirable, without it your weakest cell will get slightly over discharged without you knowing it).  These alarms are only USD $1.17 or so shipped.  Set them to 3.6v (that's per cell) and plug it in the battery balance port every time you use a Lipo.  Yes that means bench work too.  :)  I can tell you from experience that it will save ruining a battery...

Now about storage.  At the end of each flying day, charge / discharge your Lipos to "storage" level (3.8v per cell, accurately measured, every cell 3.8v).  Lipos have only so much full charge lifetime.  A year at full charge will reduce that Lipo a lot.  Don't leave them fully charged "in case you have time to fly" and don't store them in a hot car.  Storage voltage in a cool place.  The standard Lipo charger has a storage function for this.  For long term storage, charge them to storage level and put them in a sealed baggie in the refrigerator.  If you buy several Lipos but are only using one right now, put the other in the fridge.  Let them warm up a couple hours when you take them out.  You might want to check them every year, you might have a cell leaking voltage and might need to recharge it.